Generally, people will usually install a door guard latch between a wall and a door panel pivotally embedded into the wall in order to improve the security of their residence. A conventional door guard latch 1 is illustrated in FIG. 1 and FIG. 2 and can be assembled to and between a wall 21 and a door panel 22, wherein the door panel 22 is usually pivotally fixed to the wall 21 by one or more hinges 221 so that the door panel 22 can be opened or closed with respect to the wall by a user. The latch 1 includes a fixing mount 11 and a base 13. The rear side of the fixing mount 11 would be fixed to the wall 21. The front side of the fixing mount 11 includes two protruding pieces 111, and the protruding pieces 111 are spaced by a first spacing L1. The fixing mount 11 is further assembled with a movable member 15 in a U shape and having a gap 151 therein. The two corresponding ends of the moveable member 15 are spaced by a second spacing L2 and can be attached to each of the protruding pieces 111, respectively, so that the movable member 15 can be rotated on the protruding pieces 111 of the fixing mount 11. Furthermore, the rear side of the base 13 is fixed to the door panel 22 on the same side of the door panel 22 as the fixing mount 11 and opposite the hinge 221. The front side of the base 13 includes a bent portion 131 extending out and curved in the direction of the fixing mount 11, and the end of the bent portion 131 away from the base 13 is provided with a sphere 133. When the door panel 22 is closed and the movable member 15 has been rotated towards the base 13, the bent portion 131 can extend into and through the gap 151 so as to let the sphere 133 fit into the second spacing L2.
In FIG. 1 and FIG. 2, the size of the sphere 133 is smaller than the second spacing L2 and larger than the width of the gap 151. Therefore, when the movable member 15 is intersected with the bent portion 131, if a person attempts to open the door panel 22, the sphere 133 would slide from the second spacing L2 position into the gap 151, with the sphere 133 sticking out from the gap 151, creating a locking position with the movable member 15 and preventing the door panel 22 from being opened. Thus, a homeowner can prevent an outsider from forcing the door panel 22 open to get inside the house. However, after long-term research, the inventor found that the conventional door latch 1 still has a certain degree of risk even though the latch has the recited safe effects, especially when the door panel 22 is only slightly opened so that the sphere 133 hasn't completely entered the gap 151 of the movable member 15. As shown in FIGS. 3 and 4, the door panel 22 can be easily opened when an outsider inserts a foreign object 25 (such as an extended metal sheet) between the wall 21 and the door panel 22 (as shown in FIG. 3) to push against the movable member 15. Then, the movable member 15 can be rotated away from the base 13 (as shown in FIG. 4) so that the sphere 133 cannot be embedded and stuck within the gap 151 of the movable member 15 with the result that the door panel 22 can be easily opened allowing an intruder to gain entry.
In summary, for people with a greater concern for safety, the conventional door latch cannot meet their needs. Therefore, an important goal for those who are working in the security field is to resolve the aforementioned problems, finding a solution which significantly improves the protective effect of the door latch, thus preventing the door latch from being pried open from the outside with a foreign object when the door panel is opened slightly.